Don't forget you developed a ton of fuel problems after running bio fuel. 
Honestly, over the years i've come to the conclusion that supermarket fuel is not worth the hassle for saving £1.80 a tank. Have just seen far too many "one-off"s or "probably unrelated"s or "never had a problem before"s to dismiss. Most of the cars i've fixed fuelling problems on have been run on supermarket fuel all their lives, the only exceptions being one that had been flooded and another that was stage 3 tuned and abused.
Back when i was obsessed with mpg i did a load of back to back comparisons, shell fuelsave got the best results. Supermarket fuels all came up short compared to the branded stuff, morrisons even gave me hesitation problems. Didn't see a lot of difference with the premium fuels, but then they're generally not designed around economy.
Honestly, over the years i've come to the conclusion that supermarket fuel is not worth the hassle for saving £1.80 a tank. Have just seen far too many "one-off"s or "probably unrelated"s or "never had a problem before"s to dismiss. Most of the cars i've fixed fuelling problems on have been run on supermarket fuel all their lives, the only exceptions being one that had been flooded and another that was stage 3 tuned and abused.
Back when i was obsessed with mpg i did a load of back to back comparisons, shell fuelsave got the best results. Supermarket fuels all came up short compared to the branded stuff, morrisons even gave me hesitation problems. Didn't see a lot of difference with the premium fuels, but then they're generally not designed around economy.